The invention relates to a household appliance having a container for receiving objects to be treated, and an ozone generator, and an ozone eliminating device, wherein the ozone eliminating device is arranged in an exhaust air conduit, said exhaust air conduit being connected to the container. The invention also relates to a method for eliminating ozone in such a household appliance.
A household appliance and a method of the type cited in the introduction are set out in the publication DE 32 32 057 A1.
The use of ozone in a household appliance, in particular in a washing machine or another appliance for laundry care, has gained desirability recently. Ozone is not only a strong disinfection agent, it also interacts with a cleaning or care agent used in a household appliance to produce complex and rapid reactions, which can produce an improved care or cleaning effect.
Ozone can be generated in different ways in a household appliance, for instance by means of a UV lamp generator by irradiating oxygen with UV radiation below 200 nm, or by means of a corona discharge, in which oxygen is exposed to an electrical discharge in the form of a corona. The corona is generated by applying a high voltage of generally at least 5000 V to a suitable arrangement of electrodes.
Ozone is expended very quickly in wash liquor, particularly at a high temperature. Since ozone is however a particularly unpleasant smelling irritant, and may be corrosive, the escape of small quantities from a household appliance must be prevented irrespective of the presence of appropriate means and conditions in the household appliance, which may be conducive to eliminating ozone which is no longer wanted.
WO 2007/143785 A1 describes a system and a device for introducing ozone into a washing machine. The system contains a first pipeline for introducing ozone originating from an ozone supply into a wash fluid inlet and a second pipeline for discharging ozone into a region above a wash chamber. A venturi nozzle is used to introduce ozone and to mix it with wash fluid. The venturi nozzle here is operatively coupled to wash fluid inlet means so as to draw the ozone into the wash fluid, as the wash fluid is introduced into the washing tub.
WO 2008/119631 A1 describes a washing machine, in which microorganisms present in a detergent distributor, i.e. a soap drawer, are eliminated by the direct introduction of ozone from an ozone generator into the soap drawer. In one embodiment, water is introduced into the soap drawer at the same time as the ozone, so that the ozone/water mixture is routed through the soap drawer. The possibility of ozone escaping from the washing machine is intended to be minimized by these means.
US 2008/0302139 A1 discloses a tunnel washer, which includes a plurality of zones for continuously washing laundry, two points for injecting ozone, a water circuit, which connects a water input and a water output, with the water circuit including a water storage container and a venturi injector for dissolving ozone in water, as well as an ozone generator. A negative pressure or a vacuum can be applied to the tunnel washer by way of an ozone eliminating device, in order to prevent ozone leakages. A fan can be used to generate the negative pressure. Excess or escaping ozone can be catalytically converted back to normal oxygen in the ozone eliminating device.
US 2006/0096038 A1 describes a system for monitoring ozone and for controlling the supply of ozone to a washing machine. An ozone sensor indicates that a fixed ozone limit value is exceeded, whereupon an ozone generator is switched off, until the ozone concentration is once again below this limit value. There is no provision for elimination of ozone.
DE 32 32 057 A1 describes a cleaning machine for laundry, dishes or suchlike with a storage container for a detergent and an ozone generator, to the output of which an ozone supply line, which opens therein, is connected for the purpose of ozonizing the detergent. In one embodiment, a vent line and a facility consisting of a heating spiral for eliminating ozone are assigned to the storage container. FIG. 1 shows a washing machine, in which an ozone generator comprises a compressor, so that the ozone can flow into the storage container with the necessary high pressure. An overflow is used as a vent line, through which the air resulting at low pressure above the detergent level can escape. The overflow here can be provided with a heating device, which is heated to such a high temperature that any remaining ozone in the air is destroyed before the air reaches the surroundings. An active carbon filter can also be present instead.
DE 24 33 909 A1 describes an appliance for caring for items of clothing having a cabinet-type housing which can be closed with a door with a receiving space for items of clothing, to which the intake and outlet side of a circulating air ventilator are connected with an air heater in between, with the receiving space connecting to the outer space by way of a fresh air filter and the intake side of an exhaust air ventilator being connected to the receiving space, while its outlet ends in an opening of an exterior wall of the housing. At least one ozonizer is provided for the air of the receiving space. In one embodiment of this appliance, the outlet of the exhaust air ventilator is connected to the outer space, with an exhaust air filter being arranged in the exhaust air path, the filter material of which consists of active carbon.
EP 0 699 470 A1 describes a method for eliminating ozone from gases or fluids, in which the gas to be treated or the fluid to be treated is treated with a physical method in order to remove the ozone and is then brought into contact with a polymer which binds the ozone. In the physical method, a catalyzer, thermal energy and/or radiation energy are used in particular. The polymer which binds the ozone is in particular polyarylene thioether, polyarylene ether or a macroporous copolymer.
US 2008/092601 A1 describes an open washing system using ozone as well as a method for washing safely using high concentrations of ozone. In a washing machine comprising an ozone generator, an exhaust air conduit is for instance connected to the container receiving laundry, wherein an ozone eliminating device having a catalyzer for catalytically converting ozone to oxygen and a fan for taking in air containing ozone are arranged in the exhaust air conduit.
Against this background the object of the invention is to provide a household appliance with an ozone generator, wherein an escape of ozone can be effectively prevented. The possible escape of excess ozone from the household appliance is preferably to be eliminated here. The subject matter of the invention is also a method for operating this household appliance.